In addition, a claim purportedly directed to more than one statutory class of invention is indefinite because it is unclear what would constitute infringement of the claim. Cf. Ex parte Lyell, 17 USPQ2d 1548, 1551 (BPAI 1990) (“[A] single claim which purports to be both a product or machine and a process is ambiguous and is properly rejected under 35 USC 112, second paragraph, for failing to particularly point out and distinctly claim the invention.”); IPXL Holdings, L.L.C. v. Amazon.com, Inc., 430 F.3d 1377, 1384 (Fed. Cir. 2005) (A single claim covering both an apparatus and a method of using that apparatus is indefinite because it is unclear what acts constitute infringement of the claim).